Abstract: The present invention relates generally to synthesis of radioactive material, such as a tritiated polymer, and an apparatus for generating electrical current from the nuclear decay process of a radioactive material. In one embodiment, the invention relates to an energy cell (e.g. a battery) for generating electrical current derived from particle emissions occurring within a radioactive material such as a tritiated polymer) on pore walls of a porous semiconductor. The radioactive material may be introduced into the energy cell by a wetting process.

Abstract: The present invention relates generally to synthesis of radioactive material, such as a tritiated polymer, and an apparatus for generating electrical current from the nuclear decay process of a radioactive material. In one embodiment, the invention relates to an energy cell (e.g., a battery) for generating electrical current derived from particle emissions occurring within a radioactive material such as a tritiated polymer) on pore walls of a porous semiconductor. The radioactive material may be introduced into the energy cell by a wetting process.

Abstract: The present invention relates generally to synthesis of radioactive material, such as a tritiated polymer, and an apparatus for generating electrical current from the nuclear decay process of a radioactive material. In one embodiment, the invention relates to an energy cell (e.g., a battery) for generating electrical current derived from particle emissions occurring within a radioactive material such as a tritiated polymer) on pore walls of a porous semiconductor. The radioactive material may be introduced into the energy cell by a wetting process.

Abstract: The present invention relates generally to synthesis of radioactive material, such as a tritiated polymer, and an apparatus for generating electrical current from the nuclear decay process of a radioactive material. In one embodiment, the invention relates to an energy cell (e.g., a battery) for generating electrical current derived from particle emissions occurring within a radioactive material such as a tritiated polymer) on pore walls of a porous semiconductor. The radioactive material may be introduced into the energy cell by a wetting process.

Abstract: A method of making an energy conversion device includes forming a plurality of pores within a substrate and forming a junction region within each of the plurality of pores. Each of the junction regions has a depletion region and each of the plurality of pores defines an opening size in the substrate and a spacing from adjacent pores so that the depletion regions of each of the pores is at least substantially in contact with the depletion region of the pores which are adjacent.

Abstract: Apparatus and method for determining the integrity or quality of a gravel pack positioned between the casing and gravel pack screen of a subterranean borehole, with the method including azimuthally scanning the gravel pack for radiation, with detection of the radiation limited to a limited angular arc of the gravel pack at any one time, with the apparatus including shielded or collimated radiation source and/or detector.

Abstract: Apparatus and method for determining the integrity or quality of a gravel pack positioned between the casing and gravel pack screen of a subterranean borehole, with the method including azimuthally scanning the gravel pack for radiation, with detection of the radiation limited to a limited angular arc of the gravel pack at any one time, with the apparatus including shielded or collimated radiation source and/or detector.

Abstract: Apparatus and method for determining the integrity or quality of a gravel pack positioned between the casing and gravel pack screen of a subterranean borehole, with the method including azimuthally scanning the gravel pack for radiation, with detection of the radiation limited to a limited angular arc of the gravel pack at any one time, with the apparatus including shielded or collimated radiation source and/or detector.

Abstract: The invention is a stationary radiation detection tool that provides an azimuthal indication of the location of subterranean radiation sources. In one embodiment, the tool has four gamma ray sondes, each of which receives gamma rays from a discrete sector of surrounding formation.

Abstract: A method for determining the azimuthal direction of a maximum in a series of gamma ray count measurements that are each assigned to an azimuthal sector, comprising: determining the x- and y-components of the gamma ray counts for each sector, averaging the component values to obtain averaged x- and y-components, and calculating the corresponding aximuthal angle for the maximum by computing the arctangent of the ratio of the averaged y- and x-components.

Abstract: A method for calculating the position and quantity of scale downhole, while avoiding the need to run a before log is provided. The method includes assessing the gamma ray spectra of both scale and tracers in a single logging pass. A matrix of multipliers for both borehole and formation radium is included in the data used to evaluate the gamma ray log. The radium in the formation is distinguished from radium near the borehole (scale) using the deflection of the relative distance curve and the resulting calculations of gamma ray energy attributable to scale are used to correct the measured gamma ray emissions attributed to the tracers. The method allows several tracers to be monitored with a single logging pass, even in a hole that has been previously produced and has been contaminated with radioactive scale.

Abstract: A typical nuclear well logging tool forms a count rate data stream including statistical noise. A robust single pass partially deconvolved smoothing filter matched to the tool response is applied to the count rate data to enhance vertical resolution while minimizing the statistical noise increase. The smoothing filter is partially deconvolved by the application of a three point deconvolution characteristic of the cusp portion of a related cusp function and a box function representative of the tool response.

Abstract: A method is disclosed for determining the thickness of cement that has been placed in an annulus between a casing string and a wellbore penetrating a formation, wherein the method includes the steps of: logging the amount of radioactivity emitted by a radioactive material in the formation prior to emplacement of the casing and cement, including in the cement an amount of the radioactive material, placing the casing and cement in the wellbore, logging the amount of radioactivity emitted by the radioactive material and transmitted through the casing and calculating the amount of cement in the annulus by determining the amount of the radioactive material in the annulus.

Abstract: A system for use in cased well boreholes for measuring gamma ray spectra induced by bombardment of earth formations in the vicinity of the borehole with fast neutrons. Monoenergetic fast neutrons emitted in repetitive pulses penetrate the borehole structure and enter earth formations in the vicinity of the borehole and are moderated by elastic and inelastic scattering to thermal energy and captured by the nuclei of elements in and about the borehole. A scintillation detector optically coupled to a photomultiplier detects gamma radiation induced by the neutrons and produces electrical pulses with amplitudes representative of the energy of gamma rays. A pulse height analyzer connected to the output of the detector and photomultiplier separates the electrical pulses into a spectrum representative of the gamma ray energy spectrum.

Abstract: A method for evaluating the penetration of downhole materials such as proppant, casing annulus fill, or packed gravel by radioactively tagging the material, conducting well logging with gamma ray spectroscopy equipment to generate data signals, and applying an improved low-noise processing routine to the data signals to determine the material's penetration diameter. After hydraulic fracturing, gravel packing, or cementing operations are performed on a cased well, the well is logged using gamma ray spectroscopy techniques. In an exemplary embodiment, the resultant data signals are divided into channels, sent uphole, consolidated into depth intervals, and summed into specified energy windows. The spectra are processed by a weighted least squares technique to represent the spectra as borehole and formation component signals.

Abstract: Apparatus for measuring the volume of gas present in a multiphase flow regime in a cased oil or gas well borehole and the amount, if any, of stratification thereof at a particular borehole depth. The apparatus includes a low energy gamma ray source and a sodium iodide detector located a very short distance from the source and separated by shielding material. Low energy gamma rays, unable to leave the well casing and return, are emitted from the source and scattered back from the multiphase production fluid to a detector comprising a sodium iodide crystal and photomultiplier tube. Both the source and detector are surrounded by rotatable slit collimators to provide sensitivity to azimuthal variations in gas volume percentage in the flow.

Abstract: Formation fluid flows in earth formations (37) opposite a perforated (40) wellbore (15) zone are measured and monitored by injecting radioactive tracers (50) into the perforations (40), blocking the perforations to retain the tracers (50) in the formation (37), monitoring the apparent decay rates (58) of the injected tracers (50), and then determining the rate at which the tracers are being carrier away by fluid movements in the formation (37). From this the flow rate (60) of the fluids in the earth formations (37) adjacent the borehole interval is inferred.

Abstract: Techniques are shown for determining the distribution of plural tracer isotopes located inside and outside a cased well borehole. Standard gamma ray spectra of plural tracer isotopes taken inside and outside (and possibly intermediate) a well borehole are fitted to an unknown gamma ray spectrum of a well having plural tracer isotopes used therein. Techniques using a priori knowledge of well geometry and not using such knowledge are disclosed for performing the analysis of the unknown well spectrum.

Abstract: A method of radioactive well logging for use in well operations wherein hydraulic fracturing material, including radioactive isotopes, is injected from a steel-cased well bore 31 into surrounding earth formations 33. Low energy gamma ray emitting radioisotopes are selected for tagging the liquids phase of the fracturing material and high energy gamma ray emitting radioisotopes are selected for tagging the solids phase. The relative amount of low energy radioisotope material inside the well bore 31 relative to the amount outside the casing 35 is determined to minimize the interfering effects of borehole tracers in determining concentrations of the high energy tracers in the formations. The procedure includes detecting the intensity of gamma radiation from the tracers in the borehole and surrounding formations by a detector 38 in the borehole in proximity to the injection zones and obtaining data representative of the radiation intensity.

Abstract: A method and apparatus (43) are disclosed for natural gamma ray spectral logging of a well borehole (41) to determine the abundances of uranium (U), potassium (K), and thorium (Th) gamma rays in the earth formations (46) adjacent to the borehole (41), and for compensating for borehole attenuation effects upon such gamma photons caused by scattering and absorption phenomena in the materials (42) within the borehole.